Could you spray the rocks with bitter apple or something like that? It would have to be redone every now and then, but once you stop the habit it may help.
We had a German Shepherd who swallowed rocks, big ones, it cause a lot of problems and pain. So needs to be watched. In the end we had to use a muzzle, when out for walks, to stop this. Even while walking, she'd scoop a rock up and swallow. Some 4" long.
__________________ Caleb   Pippi |